Maternal Physio - Metabolic

Question 1

By 3rd trimester, maternal BMR is increased by how many percent?

Answer 1

10-20%

• Note:*
• Additional 10% in women with twin gestation

Question 2

WHO estimate of additional energy demand per trimester

Answer 2

• 1st - 85 kcal/day
• 2nd - 285 kcal/day
• 3rd - 475 kcal/day

Question 3

Average weight gain

Answer 3

Approximately 12.5 kg or 27.5 lbs

Question 4

Weight gain

• Normal pre-pregnancy weight
• BMI < 19
• BMI > 26

Answer 4

• Normal pre-pregnancy weight
  
  • 25-35 lb
• BMI < 19
  
  • 28-40 lb
• BMI > 26
  
  • No more than 20 lb
• Summary:*
• 20, 25 or 28-35 depending on BMI

Question 5

Ideal weight gain by trimester

Answer 5

• T1: 1.5-3 lb gained
• T2 and T3: 0.8 lb/week

Question 6

Majority of the weight gained from pregnancy comes from:

Answer 6

• Fetus – 3400 g
• Maternal stores (fat) – 3345 g
• Blood and extravascular fluid – 2930g

Question 7

Factors causing edema (water retention)

Answer 7

• _↑ venous pressure below the level of the uteru_s due to compression of the vena cava and pelvic veins by the gravid uterus
• ↓ in interstitial colloid osmotic pressure
• fall in plasma osmolality of approximately 10 mOsm/kg induced by a resetting of osmotic thresholds for thirst; and
• vasopressin secretion

Question 8

The minimum amount of extra water accrued during normal pregnancy is ≈ ___ L

Answer 8

• 6.5 L
  
  • 3.5: water content of the fetus, placenta, and amnionic fluid plus
  • 3.0: increases in the maternal blood volume and in the size of the uterus and breasts

Question 9

Carbohydrate metabolism (insulin sensitivity and resistance)

• In the first 20 weeks
• After 20 weeks

Answer 9

• In the first 20 weeks
  
  • Insulin sensitivity ↑ in first half of pregnancy
  • Lower fasting glucose levels allow for glycogen synthesis and fat deposition
• After 20 weeks
  
  • Insulin resistance develops and plasma insulin levels rise
  • Higher levels of both insulin and glucose stimulate utilization of glucose and lipids for energy

Question 10

As a result of insulin, what is a common finding in pregnant women?

Answer 10

• mild fasting hypoglycemia
• postprandial hyperglycemia
• hyperinsulinemia

Question 11

Why is pregnancy-induced state of peripheral insulin resistance occur?

Answer 11

To ensure a sustained postprandial supply of glucose to the fetus

Question 12

Hormones that mediate postprandial hyperglycemia

Answer 12

• Progesterone and estrogen
  
  • mediate insulin insensitivity
• Placental lactogen
  
  • increase lipolysis → liberation of free fatty acids → tissue resistance to insulin

Question 13

The optimal time to screen for glucose intolerance

Answer 13

26–28 weeks gestation

Question 14

Normal pregnancy state is:

Answer 14

• Hyperlipemic
• Glycosuric
• Anabolic

Question 15

Concentrations of lipids, lipoproteins, and apolipoproteins in plasma

• During pregnancy
• After delivery

Answer 15

• They increase during pregnancy
• They decrease after delivery

Question 16

The storage of fat occurs primarily during which stage of pregnancy?

Answer 16

Mid-pregnancy

Note: Fat storage declines or ceases during the 3rd trimester

Question 17

Where are fats deposited and its implication? What hormone is responsible?

Answer 17

• Deposition
  
  • mostly in central rather than peripheral sites
• Rationale
  
  • it becomes available for placental transfer during the last trimester when fetal growth rate is maximal along with essential fatty acids requirements
• Mechanism
  
  • progesterone acts to reset a lipostat in the hypothalamus, and at the end of pregnancy, the lipostat returns to its previous nonpregnant level, and the added fat is lost

Question 18

Leptin

• Disease associated with deficiency
• Disease associated with elevation

Answer 18

• Secreted by
  
  • Adipose tissue, placenta
• Action
  
  • Play a role in body fat and energy expenditure

Etymology:

• leptos - “thin” ⇒ “the hormone of energy expenditure”
• lept_in_ - _in_hibiting hunger

Question 19

Leptin

• Disease associated with deficiency
• Disease associated with elevation

Answer 19

• Disease associated with deficiency
  
  • Anovulation
  • Infertility
• Disease associated with elevation
  
  • Preeclampsia
  • GDM

Etymology:

• leptos - “thin” ⇒ “the hormone of energy expenditure”
• lept_in_ - _in_hibiting hunger

Question 20

Ghrelin

• Secreted by
• Action

Answer 20

• Secreted by
  
  • Stomach in response to hunger
• Action
  
  • Cooperates with leptin in energy homeostasis modulation

Question 21

How much sodium and potassium are retained in normal pregnancy? Are these increased or decreased?

Answer 21

• 1000 mEq of sodium and 300 mEq of potassium
  
  • Decreased

Question 22

What happens to serum calcium level during pregnancy? Describe the mechanism.

Answer 22

Decreased; lowered plasma albumin concentration and, in turn, the consequent decrease in the amount bound to protein

Question 23

What happens to serum magnesium level during pregnancy? Describe the mechanism.

Answer 23

Decreased; pregnancy is actually a state of extracellular magnesium depletion